Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
  • A61M1/342—Adding solutions to the blood, e.g. substitution solutions
  • A61M1/3441—Substitution rate control as a function of the ultrafiltration rate
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
  • A61M1/342—Adding solutions to the blood, e.g. substitution solutions
  • A61M1/3424—Substitution fluid path
  • A61M1/3431—Substitution fluid path upstream of the filter
  • A61M1/3434—Substitution fluid path upstream of the filter with pre-dilution and post-dilution
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/34—Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
  • A61M1/342—Adding solutions to the blood, e.g. substitution solutions
  • A61M1/3424—Substitution fluid path
  • A61M1/3437—Substitution fluid path downstream of the filter, e.g. post-dilution with filtrate
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
  • A61M1/3672—Means preventing coagulation
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
  • A61M1/3621—Extra-corporeal blood circuits
  • A61M1/3639—Blood pressure control, pressure transducers specially adapted therefor
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M1/00—Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
  • A61M1/36—Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
  • A61M1/3621—Extra-corporeal blood circuits
  • A61M1/3663—Flow rate transducers; Flow integrators
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/70—General characteristics of the apparatus with testing or calibration facilities
  • A61M2205/707—Testing of filters for clogging
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M2205/00—General characteristics of the apparatus
  • A61M2205/75—General characteristics of the apparatus with filters
  • A61M2205/7563—General characteristics of the apparatus with filters with means preventing clogging of filters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S210/00—Liquid purification or separation
  • Y10S210/929—Hemoultrafiltrate volume measurement or control processes

Definitions

• the present invention relates to a device for purifying blood comprising a blood extraction conduit, a blood return conduit, means for filtering the blood situated between the extraction conduit and the return conduit, means to circulate the blood, a liquid evacuation conduit from said filtration means called ultrafiltrate, means for circulating the ultrafiltrate in said evacuation conduit, a source of substitution solution, two connecting conduits between this source and on the one hand, said blood extraction conduit, on the other hand, said blood return conduit and means for circulating the substitution solution in each of said connecting conduits.
• the purpose of extracorporeal purification is on the one hand to clean the blood of the patients by removing undesirable elements and on the other hand to control the weight of the patients.
• the invention applies more particularly to emofilti-ation which is distinguished from dialysis by the fact that the purification takes place by convection rather than by diffusion through a semi-permeable membrane. In both cases the operator is called upon to intervene during the sessions, in particular to avoid coagulation in the extracorporeal circulation circuit, which occurs in particular at the level of the filter.
• the coagulation of the extracorporeal circulation in hemofiltration is conventionally reduced by using anti-coagulants (heparin, liquemine) and by proceeding at regular intervals with a rinsing of the circuit and the change of filters.
• anti-coagulants heparin, liquemine
• rinsing it is an operation which consists in temporarily circulating physiological fluid in the filter instead of blood. This is done by obstructing the blood extraction conduit with a clamp, connecting a pocket of physiological fluid to the blood extraction conduit, while waiting for a sufficient quantity of physiological fluid to have drained, usually from 100 to 300 ml. This quantity is considered suitable for cleaning the filter. The previous flow conditions are then restored to continue the treatment. This sequence of operations takes a long time and can lead to handling errors. In addition, it interrupts treatment and the operator must take into account the excess liquid injected into the patient when calculating the patient's water balance.
• the exchange volume which corresponds to an exchange flow
• the volume of liquid participating in the purification of the blood withdrawn from the latter during the session is defined as the volume of liquid participating in the purification of the blood withdrawn from the latter during the session. If there are no losses, in particular by predilution, this volume corresponds to that of ultrafiltrate. It is the data which, in hemofiltration, determines the degree of purification of the blood during the session, which could also be defined as being the quantity of impurities removed from the blood. None of the systems mentioned above is really satisfactory since they do not adapt to variations in operating parameters which may appear during treatment. In addition, patients are regularly insufficiently purified because the near volumes crits are calculated assuming that all of the substitution liquid is injected in post-dilution, the values not being corrected to take into account the proportion of this liquid introduced in predilution.
• the object of the present invention is to remedy, at least in part, the above-mentioned drawbacks.
• the subject of this invention is an extracorporeal blood purification device of the above-mentioned type, according to claim 1.
• An essential advantage of this invention lies in the fact that this device does not require user intervention during the treatment.
• the device according to the invention makes it possible to minimize the substitution solution consumed and to adapt the exchange volume so as to comply, as far as possible, with all of the instructions given by the user.
• FIG. 1 shows a diagram of this embodiment
• FIG. 2 is a block diagram of the calculation means 9
• FIG. 3 illustrates the sequence of operations for starting up the device
• FIG. 4 illustrates the sequence of operations for adjusting the flow rates of ultrafiltrate and of substitution liquid, integrating the calculation of the new exchange volume made necessary by the use of predilution
• FIG. 5 illustrates the sequence of operations for adjusting the predilution rate.
• the invention has means for extracorporeal circulation of blood composed of an extraction duct 1, a pump 2 for extracting blood from the body of patient P and a return duct 3 for bringing the purified blood back into the patient's body P.
• a filter 4 makes it possible to purify the blood, thanks to a conduit for discharging the polluted solution 5, called an ultrafiltrate, having a flow control means 6.
• a substitute solution conduit 7 connects a reservoir of substitution solution S to the extracorporeal circulation circuit 1, 3.
• This conduit is divided into two conduits 7 ′ and 7 ", the first 7 ′ connecting the source of substitution liquid S to the blood extraction conduit 1 upstream of the filter 4, the second 7 “connecting this source S to the return conduit 3, downstream of the filter 4.
• the flow of predilution liquid through the conduit 7 ' is controlled by a peristaltic pump 8.
• the flow of post-dilution liquid through the duct 7 " is controlled by a peristaltic pump 8 '.
• the predilution liquid can either be injected upstream or downstream of the blood extraction pump 2.
• Calculation means 9 serve to determine the proportion of the predilution liquid flow rate and that of the post-dilution liquid.
• Pressure or flow sensors 10, 11, 12, and 13 are placed in different places of the blood circulation circuit 1, 3 and of the evacuation duct 5 of the ultrafiltrate. These sensors 10-13 are connected to the calculation unit 9 to supply it with the parameters necessary for determining the respective quantities of the substitute liquid flow rates to be sent in the conduits 7 ′ and 7 ′′ and corresponding to the predilution and calculated post-dilution.
• the usual components of extracorporeal purification devices which do not intervene directly in the field of the present invention are not shown. These are in particular the air bubble detectors, the clamp for closing the return line 3 of the blood, the blood leak detector, the blood or substitute liquid heater and the means for measuring the masses passed.
• the flow control means are typically peristaltic pumps or clamps controlled by the computing unit 9.
• the invention also applies to extracorporeal circulation systems with a single needle and to dialysis machines integrating or not the manufacture of solutions, as well as to combined methods such as hemodiafiltration.
• a system according to the invention adapts the flow rates of substitution liquid in the conduits 7 ′, 7 "so as to maintain the value of the parameters influenced by this phenomenon in their normal operating values and adapts the exchange volume, and consequently the flow rate of ultrafiltrate, taking into account the flow rate of substitution liquid which has actually flowed into the predilution line 7 ′, so as to correct its value by deducting the proportion of substitution liquid that has not participated in the purification.
• the system minimizes the volume of substitution liquid that flows in the predilution duct 7 ′, in order to avoid wasting this substitute liquid and to achieve a better degree of purification over the given time.
• the block diagram of the calculation unit 9 illustrated in FIG. 2 includes an interface 15 with the help of which the operator can enter the specifications relating to the processing.
• This interface 15 is connected to a control unit for the exchange 16 which includes a calculation program for controlling the ultra iltrat pump 6 and the post-dilution pump 13 according to the indications coming inter alia from the interface 15, as well as data and / or calculation rules which may be contained in a memory (not shown).
• the interface 15 can also be connected to a control unit 17 of an anticoagulant distribution station 18, as well as to a control unit 19 of the blood extraction pump 2 which acts according to the indications operator or predefined flow optimization rules.
• the computer 9 also includes a predilution control unit 20 connected on the one hand to the exchange value control unit 16 and to an interpretation unit 21 of the measurements made by the sensors 10-13 and d on the other hand to the predilution pump 8.
• the predilution control unit 20 establishes the initial value of the predilution rate according to the instructions received from the predilution unit. control of the exchange value 16 or of rules or values previously recorded in the unit 20. The latter increases or decreases the flow rate of the predilution pump 8 according to the interpretation of the values measured by the detectors 10-13, provided by the interpretation unit 21.
• the exchange value control unit 16 directly supplies the predilution control unit with a set value to be applied to the predilution pump 8, said value being established on the basis of calculation rules recorded in the calculation means 9.
• An example of such a rule consists in keeping the predilution setpoint at zero for an ultrafiltrate flow rate lower than a given value, then increasing said predilution rate according to a curve proportional to the increase in the ultrafiltrate above said given value.
• substitution liquid is adapted to that of ultrafilter corrects values (desired weight losses, external contributions and losses) necessary to maintain or adapt the patient's weight as requested by the operator and split in two according to an initial report between post-dilution and predilution, determines on statistical bases.
• the quantity of substitution liquid flowing in the predilution duct 7 ′ is measured or calculated, its value being used to determine a new exchange volume corresponding to an identical degree of purification. to that determined by the volume initially prescribed.
• the flow ultrafiltrate 5 is then adapted so as to correspond to this new volume of exchange, and if possible to achieve the objectives of purification and variation of weight of the patient in the prescribed duration of treatment.
• the physical limits of the material are recorded in the computing unit 9, such as for example the limits of the flow control means and the limit of the linear relationship between the decrease in the degree of purification and the predilution value which appears by increasing the liquid flow rate in the predilution line 7 '.
• the point beyond which the degree of purification is considered to be insufficient compared to the substitution liquid consumed is determined by the blood and filter variables involved in coagulation. It can be determined experimentally and recorded in the calculation unit 9 or measured continuously, for example by assaying urea and its variation in the ultrafiltrate 5. To determine whether a physical limit is theoretically exceeded, the value admissible limit of the corresponding parameter is memorized. If an admissible limit value is exceeded, the calculation unit assigns the value of the parameter to its limit value and extends the processing time beyond the time required to achieve the desired objectives.
• the control unit 19 of the blood extraction pump 2 periodically increases the speed of this pump 2 until the increase in the flow of extracted blood no longer increases linearly with the increase the speed of pump 2, indicating that the maximum admissible flow rate of the patient's vascular access has been exceeded. At this time, the control unit 19 of the blood pump 2 decreases the speed of this pump 2 in order to reach the last value known to be in the linear range.
• This control can be carried out repeatedly during the treatment so as to maintain the blood flow under optimum filtration conditions.
• the flow sensor 14 will advantageously also be used to precisely determine the blood flow.
• the anticoagulant flow rate can be zero or not, brought by an auxiliary syringe pump or by a pump 18 controlled by the calculation unit 9.
• the calculation unit 9 can have the architecture shown in FIG. 2, the invention not being limited to this example.
• Device configuration data is initially recorded, generally outside of a therapeutic session, in the calculation unit 9.
• This data may include the definition of standard treatments, in particular the name of the treatment, the volume of exchange , the required duration and the pipes and filters used, and those of the inputs and losses of liquids external to the device, in particular the type of intake or losses, the default flow rate and the mass to be reached. These values can be modified during processing, the device then taking into account the new values.
• the operator indicates the prescribed treatment values, for example the patient's water balance, the desired weight loss or an infusion. If necessary, it modifies the initially defined values which appear by default.
• This start-up of the purification device is illustrated by the diagram in FIG. 3.
• the blood flow is defined according to one of the methods described above.
• the calculation unit 9 determines the flow initial ultrafiltrate and substitution liquid, the predilution rate being either zero or calculated on the basis of rules previously defined and stored in the device. Ideally, the initial predilution rate will be close to the normal operating value that is expected.
• the treatment begins and the transfilter and / or transmembrane pressures are measured so as to determine in a few seconds their normal operating values which correspond to a stable state of the device satisfying its operation according to the predetermined rules.
• the flow rates of the different pumps 2, 6, 8 and 8 ' are automatically adjusted, either at regular time intervals, or on the basis of a determined event such as a sudden increase in pressure, by measuring the values pressure 10-13 and comparing these values to those considered to be normal operating values.
• a determined event such as a sudden increase in pressure
• the predilution rate is then adjusted according to the value of the three-state variable, then the necessary exchange volume is calculated, the ultrafiltrate flow rate being adapted to this new value.
• the rules for determining said variable in three states can be defined in several ways, for example, the predilution rate is decreased in each adjustment cycle as long as the pressures do not increase by more than 10% compared to the value determined to be that of operation, or as long as the pressures do not show an increase of more than 5% per 30 seconds. In the same way one can determine criteria for maintaining and increasing the predilution rate.
• a variant consists in supplying the pressure measurements 10-13 to the unit 16 which then calculates the setpoints of the pumps 6, 8 and 8 'taking into account the measurements and calculation rules previously recorded.
• Ultrafiltrate flow measurements for given pump speeds or clamp openings are also indicators of the level of fouling in the filter.
• the adaptation of the predilution part may not be sufficient to sufficiently clean the filter 4.
• cleaning is carried out by stopping the blood extraction pump 2, the ultrafiltrate pump 6 and the post-dilution pump 8 'for a period of time or for a determined volume or mass of restitution liquid and by actuating that predilution 8 so as to circulate physiological solution in place of blood and thus rinse the filter 4.
• the mass of solution injected into the patient during the rinsing thus carried out is then deducted during the continuation of the treatment.
• the benefit of the invention is threefold: Reduction in the amount of costly sterile substitute medical solution used, removal of fouling from the surface. extracorporeal culation without compulsory addition of anticoagulants and automatic adjustment of the exchange volume to obtain the desired degree of purification.

Priority Applications (7)

Applications Claiming Priority (2)

Publications (2)

Family

ID=8243115

Family Applications (1)

Country Status (11)

Cited By (5)

Families Citing this family (17)

Citations (2)

Family Cites Families (8)

• 1999
  • 1999-10-29 EP EP99810984A patent/EP1095666A1/fr not_active Withdrawn
• 2000
  • 2000-10-26 US US10/111,771 patent/US6814864B1/en not_active Expired - Lifetime
  • 2000-10-26 EP EP00967495A patent/EP1223995B1/fr not_active Expired - Lifetime
  • 2000-10-26 JP JP2001534441A patent/JP4295940B2/ja not_active Expired - Lifetime
  • 2000-10-26 CA CA002389016A patent/CA2389016C/en not_active Expired - Lifetime
  • 2000-10-26 EP EP06014429A patent/EP1704881A3/fr not_active Ceased
  • 2000-10-26 PT PT00967495T patent/PT1223995E/pt unknown
  • 2000-10-26 WO PCT/CH2000/000573 patent/WO2001032238A2/fr active IP Right Grant
  • 2000-10-26 DK DK00967495T patent/DK1223995T3/da active
  • 2000-10-26 ES ES00967495T patent/ES2269185T3/es not_active Expired - Lifetime
  • 2000-10-26 AU AU77680/00A patent/AU769788B2/en not_active Expired
  • 2000-10-26 DE DE60030460T patent/DE60030460T2/de not_active Expired - Lifetime
  • 2000-10-26 AT AT00967495T patent/ATE337807T1/de active

Patent Citations (2)

Also Published As

Similar Documents

Legal Events